The present invention relates to an apparatus for the transfer of relatively flat objects from a first to a second work station and, more particularly, to such an apparatus that is adapted for use within equipment for the manufacture of shells used to close the ends of metal cans.
One common way of packaging liquids, particularly beverages such as beer, soft drinks, juices and the like, is within cans typically formed from aluminum. In such cans, the can body is either manufactured to include both the can side walls and an attached bottom end, or the bottom end is formed separately and subsequently joined to the side walls. The upper end, which includes the means by which the can is opened, is manufactured separately and attached to the can body after the can has been filled.
The can ends, often referred to within the art as shells, are generally manufactured within ram presses. While various particular methods of shell formation are known and available, it is often necessary within these methods to transfer the shells from a first to a succeeding work station. In view of the large quantities of cans and shells that are manufactured, it is desirable to be able to form quantites of the shells very rapidly. This necessitates a transfer system that is both quick and reliable.
While various conveyor and other types of transfer systems in which the objects are physically carried are known, such systems are generally disadvantageous for applications in the manufacture of shells. In order to remove a shell from a work station within a ram press, carry the shell, and then deposit the shell at a second station, particularly where positioning of the shell at the second station is critical, a relatively complex apparatus is required. This problem is compounded when the transfer process at each station must also be coordinated with the work operation being performed at the station. Moreover, at typical press speeds of several hundred strokes per minute, at least some portions of the transfer apparatus must be operated quite rapidly. Thus, such a system would be likely to require a number of rapidly moving parts in a complex structure with attendant high acceleration and deceleration forces, thereby resulting in an expensive piece of equipment with a relatively high potential for system malfunctions.
What is needed, therefore, is an apparatus for transferring shells between successive work stations that will enable the transfer to be made quickly and reliably. Moreover, such an apparatus must include means for accurately positioning each shell when necessary at the station to which it is transferred. The apparatus should, of course, be relatively simple, with as few moving parts as possible in order to increase reliability.